Annotation of src/usr.bin/ssh/readpass.c, Revision 1.42
1.42 ! stevesk 1: /* $OpenBSD: readpass.c,v 1.41 2006/07/10 16:37:36 stevesk Exp $ */
1.1 deraadt 2: /*
1.26 markus 3: * Copyright (c) 2001 Markus Friedl. All rights reserved.
1.8 deraadt 4: *
5: * Redistribution and use in source and binary forms, with or without
6: * modification, are permitted provided that the following conditions
7: * are met:
8: * 1. Redistributions of source code must retain the above copyright
9: * notice, this list of conditions and the following disclaimer.
10: * 2. Redistributions in binary form must reproduce the above copyright
11: * notice, this list of conditions and the following disclaimer in the
12: * documentation and/or other materials provided with the distribution.
13: *
1.26 markus 14: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.6 deraadt 24: */
1.1 deraadt 25:
26: #include "includes.h"
1.35 stevesk 27:
28: #include <sys/types.h>
29: #include <sys/wait.h>
1.19 markus 30:
1.42 ! stevesk 31: #include <errno.h>
1.40 stevesk 32: #include <fcntl.h>
1.34 stevesk 33: #include <paths.h>
1.19 markus 34: #include <readpassphrase.h>
1.41 stevesk 35: #include <stdarg.h>
1.1 deraadt 36:
37: #include "xmalloc.h"
1.29 djm 38: #include "misc.h"
1.15 markus 39: #include "pathnames.h"
40: #include "log.h"
41: #include "ssh.h"
1.38 markus 42: #include "uidswap.h"
1.15 markus 43:
1.18 itojun 44: static char *
1.16 mouring 45: ssh_askpass(char *askpass, const char *msg)
1.15 markus 46: {
47: pid_t pid;
48: size_t len;
1.23 markus 49: char *pass;
1.24 djm 50: int p[2], status, ret;
1.15 markus 51: char buf[1024];
52:
53: if (fflush(stdout) != 0)
54: error("ssh_askpass: fflush: %s", strerror(errno));
55: if (askpass == NULL)
56: fatal("internal error: askpass undefined");
1.21 markus 57: if (pipe(p) < 0) {
58: error("ssh_askpass: pipe: %s", strerror(errno));
1.28 markus 59: return NULL;
1.21 markus 60: }
61: if ((pid = fork()) < 0) {
62: error("ssh_askpass: fork: %s", strerror(errno));
1.28 markus 63: return NULL;
1.21 markus 64: }
1.15 markus 65: if (pid == 0) {
1.39 markus 66: permanently_drop_suid(getuid());
1.15 markus 67: close(p[0]);
68: if (dup2(p[1], STDOUT_FILENO) < 0)
69: fatal("ssh_askpass: dup2: %s", strerror(errno));
70: execlp(askpass, askpass, msg, (char *) 0);
71: fatal("ssh_askpass: exec(%s): %s", askpass, strerror(errno));
72: }
73: close(p[1]);
1.24 djm 74:
75: len = ret = 0;
76: do {
77: ret = read(p[0], buf + len, sizeof(buf) - 1 - len);
78: if (ret == -1 && errno == EINTR)
79: continue;
80: if (ret <= 0)
81: break;
82: len += ret;
83: } while (sizeof(buf) - 1 - len > 0);
84: buf[len] = '\0';
85:
1.15 markus 86: close(p[0]);
87: while (waitpid(pid, &status, 0) < 0)
88: if (errno != EINTR)
89: break;
1.24 djm 90:
1.28 markus 91: if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
92: memset(buf, 0, sizeof(buf));
93: return NULL;
94: }
95:
1.23 markus 96: buf[strcspn(buf, "\r\n")] = '\0';
1.15 markus 97: pass = xstrdup(buf);
98: memset(buf, 0, sizeof(buf));
99: return pass;
100: }
101:
1.7 markus 102: /*
1.19 markus 103: * Reads a passphrase from /dev/tty with echo turned off/on. Returns the
104: * passphrase (allocated with xmalloc). Exits if EOF is encountered. If
105: * RP_ALLOW_STDIN is set, the passphrase will be read from stdin if no
106: * tty is available
1.12 markus 107: */
1.5 markus 108: char *
1.19 markus 109: read_passphrase(const char *prompt, int flags)
1.1 deraadt 110: {
1.19 markus 111: char *askpass = NULL, *ret, buf[1024];
112: int rppflags, use_askpass = 0, ttyfd;
1.15 markus 113:
1.19 markus 114: rppflags = (flags & RP_ECHO) ? RPP_ECHO_ON : RPP_ECHO_OFF;
1.30 djm 115: if (flags & RP_USE_ASKPASS)
116: use_askpass = 1;
117: else if (flags & RP_ALLOW_STDIN) {
1.33 markus 118: if (!isatty(STDIN_FILENO)) {
1.32 dtucker 119: debug("read_passphrase: stdin is not a tty");
1.15 markus 120: use_askpass = 1;
1.33 markus 121: }
1.15 markus 122: } else {
1.19 markus 123: rppflags |= RPP_REQUIRE_TTY;
1.25 markus 124: ttyfd = open(_PATH_TTY, O_RDWR);
1.15 markus 125: if (ttyfd >= 0)
126: close(ttyfd);
1.32 dtucker 127: else {
128: debug("read_passphrase: can't open %s: %s", _PATH_TTY,
129: strerror(errno));
1.15 markus 130: use_askpass = 1;
1.32 dtucker 131: }
1.15 markus 132: }
1.30 djm 133:
134: if ((flags & RP_USE_ASKPASS) && getenv("DISPLAY") == NULL)
135: return (flags & RP_ALLOW_EOF) ? NULL : xstrdup("");
1.15 markus 136:
137: if (use_askpass && getenv("DISPLAY")) {
138: if (getenv(SSH_ASKPASS_ENV))
139: askpass = getenv(SSH_ASKPASS_ENV);
140: else
141: askpass = _PATH_SSH_ASKPASS_DEFAULT;
1.28 markus 142: if ((ret = ssh_askpass(askpass, prompt)) == NULL)
143: if (!(flags & RP_ALLOW_EOF))
144: return xstrdup("");
145: return ret;
1.15 markus 146: }
147:
1.27 markus 148: if (readpassphrase(prompt, buf, sizeof buf, rppflags) == NULL) {
149: if (flags & RP_ALLOW_EOF)
150: return NULL;
1.20 markus 151: return xstrdup("");
1.27 markus 152: }
1.19 markus 153:
154: ret = xstrdup(buf);
155: memset(buf, 'x', sizeof buf);
156: return ret;
1.31 djm 157: }
158:
159: int
160: ask_permission(const char *fmt, ...)
161: {
162: va_list args;
163: char *p, prompt[1024];
164: int allowed = 0;
165:
166: va_start(args, fmt);
167: vsnprintf(prompt, sizeof(prompt), fmt, args);
168: va_end(args);
169:
170: p = read_passphrase(prompt, RP_USE_ASKPASS|RP_ALLOW_EOF);
171: if (p != NULL) {
172: /*
173: * Accept empty responses and responses consisting
174: * of the word "yes" as affirmative.
175: */
176: if (*p == '\0' || *p == '\n' ||
177: strcasecmp(p, "yes") == 0)
178: allowed = 1;
179: xfree(p);
180: }
181:
182: return (allowed);
1.1 deraadt 183: }
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